HomeMy WebLinkAboutStorm Water Calcs ReportSouthern Springs #2
Storm Water Calculations
Seepage Bed #1
1. Runoff Volume
A. Drainage Area: 22,505 SF
B. Runoff Coefficient: 0.95 all impervious
C. 100 Year One Hour Storm Intensity: 1.0 inch/hour
D. Volume of 1 Hour, 100 Year storm:
1.0 inch/hour *1.0 hour *(1 foot/12 inches)* 0.95 * 22,505 SF = 1781 CF
2. Seepage Bed Sizing
A. Drain Rock Voids:40%
B. Volume of Drain Rock Required: 1781CF / 0.40 = 4453 CF
C. 3 ft x 20 ft x 75 ft = 4500 CF > 4453 CF
3. Sand and Grease Trap Velocity Check
A. 1000 gal sand and grease trap
B. Open area: 3.67 SF
C. Maximum Throat Velocity: 0.5 FPS
D. Maximum Flow: 0.5 FPS * 3.67 SF = 7.34 CFS
E. Time of Concentration: less than 10 minutes, use 10 minutes.
F. 100 Year Rainfall Intensity: 3.1 inches/hour
G. Peak Flow: 0.95*3.1 inches/hour*(22,505 SF / 43,560 SF) = 1.52 CFS < 1.83 CFS
Seepage Bed #2
1. Runoff Volume
A. Drainage Area: 11,894 SF
B. Runoff Coefficient: 0.95 all impervious
C. 100 Year One Hour Storm Intensity: 1.0 inch/hour
D. Volume of 1 Hour, 100 Year storm:
1.0 inch/hour *1.0 hour *(1 foot/12 inches)* 0.95 * 11,894 SF = 942 CF
2. Seepage Bed Sizing
A. Drain Rock Voids:40%
B. Volume of Drain Rock Required: 942CF / 0.40 = 2354 CF
C. 2.75 ft x 20 ft x 43 ft = 2365 CF > 2354 CF
3. Sand and Grease Trap Velocity Check
A. 1000 gal sand and grease trap
B. Open area: 3.67 SF
C. Maximum Throat Velocity: 0.5 FPS
D. Maximum Flow: 0.5 FPS * 3.67 SF = 1.83 CFS
E. Time of Concentration: less than 10 minutes, use 10 minutes.
1/3
F. 100 Year Rainfall Intensity: 3.1 inches/hour
G. Peak Flow: 0.95*3.1 inches/hour*(11,894 SF / 43,560 SF) = 0.80 CFS < 1.83 CFS
Seepage Bed #3
1. Runoff Volume
A. Drainage Area: 10,106 SF
B. Runoff Coefficient: 0.95 all impervious
C. 100 Year One Hour Storm Intensity: 1.0 inch/hour
D. Volume of 1 Hour, 100 Year storm:
1.0 inch/hour *1.0 hour *(1 foot/12 inches)*0.95*10,106 SF = 760 CF
2. Seepage Bed Sizing
A. Drain Rock Voids:40%
B. Volume of Drain Rock Required: 760CF / 0.40 = 1900 CF
C. 3.5 ft x 15 ft x 37 ft = 1942 CF > 1900 CF
3. Sand and Grease Trap Velocity Check
A. 1000 gal sand and grease trap
B. Open area: 3.67 SF
C. Maximum Throat Velocity: 0.5 FPS
D. Maximum Flow: 0.5 FPS * 3.67 SF = 1.83 CFS
E. Time of Concentration: less than 10 minutes, use 10 minutes.
F. 100 Year Rainfall Intensity: 3.1 inches/hour
G. Peak Flow: 0.95*3.1 inches/hour*(10,106 SF / 43,560 SF) = 0.23 CFS < 1.83 CFS
7564
g�o3
1,
4
2/3
z6: 6
8 8
282292
STA 2622.$20 1
1 ETEV '- 2622.82 I
I 6ilJtilOr' CIXiS1NOCMN
sR §p MS
--
I I I
I
:PMSTA X112.+88.07 I 1
26211_LPNf1EV�2621J5_I_____L-
g 262113
7I I I I
I I I I I
1 I I I
631 5
2621]0
I I I I I
I
- r_1__ ,_ ____
,.1!
1- I I t
t
o 262187
-------- -
1
262ii1
1 I 1
i I
I
1 I
� I I
k' 2622
g 362153
I I I I I
I 1
I I I 1
I I I I
I � I
1 1 1
v I I I
u
26211
_ 1-----
--_-PN
26217
2622.$5
PMSTA I4+3I.6]
PNPN p = 262$2]= 262— j
- I_
I I I
PN OA 14+99,63 I
1 I PN EIEV = 262560 I
I I I
2624.4
I I I I 1
I ;
1 I I
2624
I 1 1 1
Ii
2b2flM {.i f2
9 i '9
I i �23
I av 1 I
� 262$0
a2. 2626.69
I -I--
I 1
2626.8
� I
_____I_ ___
262.2{
I , 1
I
II I I I
1 i I I
I I I I
III I
m 2626.
0 262.6
�
I I
I I I I I
I I I
93fl 2
I I I I I 1
I 1 1
I I
J '-
I
262-
626.5262fl
I I I
..
I I 1 I
I I I I
I I I I
, I 1
262.1
2628
I I I I
I
1 I
_ _-_.. _ _
262$87
I I I I
I ,
8 B _____L___y_ .•.____L__
2619.16 � I
I I
26261 6tA �21+6SJ6
_____L___ 1
262& 4 EIEV a 262.74 --
see sn6er cJ.o
PGt OFr91E BffofUlA1MV
'iF,W SF,T O1 -2R -OS
\V,
--— y�
\ .4,
A.
THE LAND GROUP, INC.
HeM;im9"`"` SOUTHERN SPRINGS NO. 2
MERIDIAN, IDAHO
sR §p MS
y E
'iF,W SF,T O1 -2R -OS
\V,
--— y�
\ .4,
A.
THE LAND GROUP, INC.
HeM;im9"`"` SOUTHERN SPRINGS NO. 2
MERIDIAN, IDAHO